The present disclosure relates to a heat exchanger.
In general, a heat exchanger constitutes a heat exchange cycle and functions as a condenser or an evaporator. Refrigerant flowing in the heat exchanger exchanges heat with an outer fluid. For example, a heat exchanger may be used in an air conditioner and function as a condenser for condensing refrigerant or an evaporator for evaporating refrigerant, according to a refrigerant cycle.
Such heat exchangers are classified into fin-and-tube type heat exchangers and micro-channel type heat exchangers, according to the shapes thereof. A fin-and-tube type heat exchanger includes a plurality of fins and a cylindrical or cylindrical-like tube passing through the fins. A micro-channel type heat exchanger includes a plurality of flat tubes in which refrigerant flows, and a fin disposed between the flat tubes. Both the fin-and-tube type heat exchanger and the micro-channel type heat exchanger exchange heat between an outer fluid and refrigerant flowing within the tube or the flat tube, and the fin increase a heat exchange area between the outer fluid and the refrigerant flowing within the tube or the flat tube.
However, such typical heat exchangers have the following limitations.
First, the tube of a fin-and-tube type heat exchanger passes through the fins. Thus, even when condensate water generated while the fin-and-tube type heat exchanger operates as an evaporator flows down along the fins, or is frozen onto the outer surface of the tube or the fins, the heat exchanger can efficiently remove the condensate water.
However, fin-and-tube type heat exchangers include only a single refrigerant passage in a tube, and a heat exchange area between the tube and a fin is not large. Thus, heat exchange efficiency of the refrigerant is substantially low.
On the contrary, since micro-channel type heat exchangers include a plurality of refrigerant passages within a flat tube, and a heat exchange area between the flat tube and a fin is large. Thus, micro-channel type heat exchangers are higher in heat exchange efficiency of refrigerant than fin-and-tube type heat exchangers.
However, a fin of micro-channel type heat exchangers is disposed between flat tubes that are spaced apart from each other. Hence, condensate water generated at micro-channel type heat exchangers may not be discharged from between the flat tubes and thus be frozen. In particular, this issue may be critical when micro-channel type heat exchangers are used as evaporators. In this case, heat exchange efficiency of refrigerant may be decreased.